Stannis Baratheon was one of five kings who went to war in Westeros during the second season of Game Of Thrones. King Robert's death leads to Joffrey's ascension and House Lannister's rule over the Seven Kingdoms. When Stannis learns the truth about Joffrey and his siblings' true parentage, the stag king calls his banners and begins a bloody conquest for the Iron Throne.
Stannis came close to the throne, but was ultimately killed by Brienne of Tarth in season 5. The stern-faced king wasn't the most popular choice to be King of Westeros. Compared to his rival claimants for the crown, however, Stannis might have been a worthy monarch after all.
Worthy: He Was Robert's Rightful Heir
Robert Baratheon goes to his grave leaving no legitimate heirs behind to succeed him on the throne. Joffrey, Myrcella, and Tommen are revealed to be Jaime and Cersei's children. With no heirs, the Iron Throne should have rightfully passed to Stannis as the eldest surviving Baratheon.
The laws of succession support Stannis' claim more than any other monarch. Joffrey and Tommen were Lannister bastards, whereas House Targaryen's claim to the Iron Throne was overthrown by Robert's Rebellion.
Unworthy: He Became A Religious Fanatic
Stannis is swept up in the teachings of the Red God throughout Game Of Thrones. The Baratheon king adopts a flaming heart on his banners, as well as forcing the people who follow him to submit to R'hllor's rule or burn alive at the stake.
A fanatic like Stannis could have spelled trouble for the Seven Kingdoms if he had become king. The people of Westeros, most of whom follow the Faith of the Seven, would likely rise in rebellion against their king if he forced them to convert religions.
Worthy: He Answered The Night's Watch Pleas For Help
The War of the Five Kings ravages Westeros whilst the true threat lurks beyond the Wall. The Night's Watch sends ravens to the Five Kings asking for help. Only Stannis replies, taking his forces north to fight back the invading wildings and prepare for the Long Night.
Stannis proved himself as a worthy king while other monarchs like Joffrey, Renly, and Robb failed to answer the Night's Watch calls. Of the many monarchs who fought for the crown, Stannis was one of the few who recognized where the true war needed to be fought.
Unworthy: Manipulated By Melisandre
Melisandre was instrumental in Stannis's story; it could be said that the Baratheon king ultimately became her puppet. The Red Priestess' power wins Stannis to her cause. By proclaiming him the destined hero of humanity, Mel can manipulate the king into doing what she wants.
Melisandre's influence over Stannis is a dangerous threat to his reign as king. The Red Priestess could manipulate Stannis into doing nearly anything she wanted, jeopardizing his worthiness of the crown.
Worthy: He Was A Just King
Stannis was a just - but not sadistic - king. In comparison to other rulers like Joffrey, the Baratheon monarch fairly exacted justice by Westerosi standards. Davos Seaworth is proof of this; Stannis punishes him for his smuggling misdeeds but rewards him for helping him survive the Siege of Storm's End.
The Seven Kingdoms needed a just king like Stannis after the tyrannical reigns of Aerys and Joffrey. His fair, unbiased nature gave him the clarity to do what was necessary for the good of the country.
Unworthy: He Burned His Daughter Alive
Shireen Baratheon's death remains one of the most horrifying moments in the series. All hope seems lost for Stannis and his forces in season 5. To further his campaign for the throne, Stannis listens to Melisandre and sacrifices his daughter to the flames.
Instead of securing his survival, Shireen's death does the opposite. Many of his soldiers desert him in disgust, whilst his heartbroken wife, Selyse, commits suicide by hanging.
Worthy: He Had Experience With Ruling And Leading People
Stannis was an experienced leader, lord, and battle commander. He ruled Dragonstone in his brother's stead during Robert's reign after standing against the Tyrells during the Siege of Storm's End. In the end, he was more qualified to rule Westeros than the other claimants to the throne.
He may have lacked charisma, but Stannis possessed other skills desirable of the King of Westeros. Had he overthrown the Lannisters and taken the throne, the country could have stood together against the final war for the dawn.
Unworthy: He Killed His Brother
Shireen isn't the first Baratheon to die on Stannis' orders. During season 2, Stannis and Robert's younger brother, Renly, raises his banners as a claimant to the throne. Stannis instructs Renly to surrender; when he refuses, Melisandre births a shadow magic monster to kill the rival king.
Kinslaying is a terrible crime by Westerosi standards. If the people of the Seven Kingdoms discovered the truth about Renly's death, it is unlikely they would regard Stannis as a worthy king.
Worthy: He Inspired Loyalty
For an uncharismatic character, Stannis inspired a striking level of loyalty in his followers. Davos in particular is unwavering in his service to the stag king. Despite the loss of his fingers, Davos considers Stannis a good man and a worthy King of Westeros.
If Stannis could have inspired the same loyalty amongst the other Westerosi people then his reign would have been secured. After Joffrey, the people needed a monarch they could trust and have faith in.
Unworthy: He Was Too Stubborn To Surrender
Stannis' stubborn nature is ultimately his downfall. The Baratheon king clings to his claim even in the face of certain death. Against the advice of all others, Stannis takes his full force to Winterfell and dies when they are subsequently ambushed by the Boltons.
Stannis was rigid and unmoving throughout his brief reign. Had he accepted defeat and altered his plans, he could have emerged from the ashes as the unlikely winner of the game of thrones. The stag king was just and determined, but his refusal to accommodate others made him an unworthy heir to the Iron Throne.